The journey to net-zero has no single route. Energy efficiency, renewables, electrification, hydrogen, CCUS and low carbon fuels all have a role to play. But for sectors that cannot simply plug into a power socket, the transition is considerably more complex. Aviation and maritime transport sit at the centre of this challenge.
These sectors move people and goods across continents and oceans, relying on energy-dense fuels that can deliver long range, heavy payloads and high reliability. High energy demand, strict safety requirements and global operations leave few viable alternatives to liquid and gaseous fuels, at least in the near to medium term.
Today, the transport sector accounts for around one quarter of global energy-related CO₂ emissions, with aviation and shipping together responsible for approximately 4–5%, a share expected to increase as mobility and trade expand. Yet, sustainable fuels remain marginal: around 5 EJ out of 125 EJ of global transport energy demand, mainly biofuels used in road transport. In shipping, oil still supplies 99% of fuel demand, while in aviation sustainable aviation fuels (SAF) represent just 0.1%.
According to the IEA Net Zero Scenario, the demand for low-emission fuels, including liquid biofuels, biogases, hydrogen and e-fuels, will need to double from today’s levels by 2030, and double again by 2050.
Alternative fuels offer a unique value proposition, particularly drop-in solutions that can leverage existing fleets and infrastructure. They can significantly reduce lifecycle GHG emissions and unlock new industrial and economic opportunities, especially in regions rich in renewable energy or sustainable biomass.
Yet progress remains slow. Limited feedstocks, high costs, immature supply chains and fragmented regulation continue to constrain deployment. The challenge is not only technological, it is financial, regulatory and infrastructural.
With operations in more than 70 countries and deep experience across energy systems, transport and certification, RINA has a front-row view of both the barriers and the solutions emerging globally. This white paper focuses on aviation and shipping, analyzing regulatory drivers, bio-based and synthetic fuel pathways, market dynamics, and ten priority actions to move low-carbon fuels from niche to scale, cutting emissions without compromising performance, safety or global connectivity.
